1. Field of the Invention
The present invention relates to printers of the type which print characters in response to coded digital data, and more particularly to arrangements within such printers for varying the width of the print lines in accordance with the width of the paper or other printable medium used and for horizontally shifting the print lines relative to the paper to provide a margin of desired size.
2. History of the Prior Art
Printers of the type which print graphic characters in response to coded character data in binary form have found widespread use in many data processing operations and systems. Such printers respond to the incoming coded character data to physically print the graphic characters represented by the character data as defined by the code thereof. The printing operation can assume various different forms including the well-known impact printer in which each segment of the coded character data results in the selection of a piece of type or other raised indicia. The selected piece of type strikes a piece of paper or other printable medium to effect printing of the desired graphic character.
Prior art printers of the type described suffer from a number of disadvantages which often limit their usefulness. One limitation of such printers lies in the difficulty or impossibility of providing a left-hand margin of desired size on the paper. Often printing is begun at a fixed location relative to the left edge of the paper so that the left-hand margin is fixed in size. In some arrangements where the size of the left-hand margin may be variable, such variations in size may be limited and may be relatively inconvenient and cumbersome in terms of the means used to adjust the size of the margin. In many prior arrangements the width of the print lines is not adjustable, so that once printing of a line is begun it continues despite the fact that the right-hand edge of the paper is passed. While this creates problems in certain types of systems, it is particularly disadvantageous in those systems where toner is used to coat a charged area with the toner being thereafter transferred to the paper. In such systems the toner on those portions of the print lines extending beyond the right-hand edge of the paper cannot be transferred onto the paper and instead falls loosely into the printing system causing damage and periodic shutdowns.
Accordingly, it would be desirable to provide a buffered printer in which the size of the left-hand margin is easily adjusted over a wide range.
It would also be desirable to provide in a buffered printer a capability of varying the widths of the print lines so that printing of each line can be terminated prior to or upon reaching the right-hand edge of the paper.